Impact of glucocorticoids on osteocytes and on the lacuno-canalicular system of maxillary and mandibular alveolar bone

In long bones, glucocorticoids are known to cause a decrease in bone formation and an increase in bone resorption, leading to a condition of osteoporosis also during growth. However, there are few studies on the effect of glucocorticoids on alveolar bone. The aim of the present study was to evaluate the impact of chronic administration of glucocorticoids on osteocytes and the lacuno-canalicular system of maxillary and mandibular alveolar bone in growing rats. Male Wistar rats were administered intramuscular dexamethasone (7 mg/kg b.w.) or saline solution once a week for 5 weeks. After euthanasia, mandibles and upper maxillae were resected and processed for micro-computed tomography, histological, and immunohistochemical evaluation. Glucocorticoids induced morphological changes in the lacuno-canalicular system and apoptosis of alveolar bone osteocytes and had no effect on SOST/sclerostin osteocyte expression. Our findings suggest that the deleterious effect of glucocorticoids on alveolar bone is associated with osteocyte apoptosis and lacuno-canalicular system changes, whereas Wnt/β catenin pathway regulation in osteocytes appears to play no significant role in the pathogenesis of glucocorticoid-induced bone loss.